I'm taking a course which is designed with the CISSP certification in mind. Though the class is categorized as software engineering, we talked a lot about physical security and, in particular, floods, fires, earthquakes and cars running into things. How is this security? For example we were told that data centres are safest in the middle of a building because if the roof was leaking the top wouldn't be safe, and water tends to go down so the lower floors would be the first to flood.
Is this really a security issue? For example, if the roof leaks the engineer would be at fault, not the security analyst. You wouldn't hire a security analyst to make sure the roof is solid.
UPDATE: Also, things like having bollards around a building to protect pedestrians from cars, how's this security? No one's really explained this yet. I was told the companies most valuable assets are their employees, but with this line of reasoning, what isn't security?
If the availability is so encompassing, what isn't part of security?